Original title: “Semi Auto Sniper Recoil and Spread Analysis," 25.10.2013
Author: Duncdiddy
I’ve been lurking in these forums for quite a while, soaking up info and using it to my advantage on the battlefield, and I think it’s time to give back a little. I have plenty of experience using Semi-auto snipers due to the fact I usually play as recon, but there was one thing that always bothered me: How fast can you fire the SA snipers without being affected by spread or recoil increase. I think I’ve found a way to calculate this value making a few assumptions. From what i understand, the recoil and spread values aren’t active while you are firing a gun in battlefield 3. Automatic firearms begin to feel these decreases as soon as the firetime is done, but at that exact instance, the next shot is fired, meaning these decrease values are never felt during automatic fire. For semi auto snipers, I’m assuming the same principal is true. Each sniper has a firetime during which you cant shoot. I’m guessing spread and recoil decrease doesn’t work during that time either, which is why you cant hit the broad side of a barn door if you spam the trigger. With this in mind, here are my calculations for the effective usage of the QBU-88:
Spread
at 0.8 increase per shot and 15.0 decrease per second we find the time it takes for the spread to reset after the firetime is over.
0.8/15.0=.0533
Adding this time to the firetime of the QBU, we can find the time it takes for the spread to completely reset after taking a shot.
.0533+.2308=.2841
Taking the reciprocal and multiplying it by 60 gives us our answer
(1round/.2841sec) * (60sec/1min) = 211RPM
This means you can fire the QBU-88 at 211RPM without feeling spread increase. If you are exceeding this ROF my very much you might as well be hipfiring with an LMG
Rocoil
Adding the average horizontal recoil (.15) to the vertical recoil (1.5) gives us an approximate value for the average recoil/shot (1.65)
dividing this value by the recoil decrease per second, we find the recoil reset time after firetime in seconds per shot.
(1.65/shot)*(1sec/6.0)=.275
Add the firetime
.275+.2308=.5058
Using the same method we did with the spread, we can convert to RPM
(1round/.5058sec) * (60sec/min) = 119RPM (surprising isn’t it)
This is the real limiting value. You can only take 2 shots per second to avoid recoil messing up your follow up shots.
This is where the foregrip comes in, as it increases this ROF value. Below is a list of all the values I’ve calculated for the SA snipers with and without the Foregrip.
MK11/SVD: Recoil: (117RPM,143RPM) Spread: (211RPM)
QBU-88: Recoil: (116RPM,144RPM) Spread: (211RPM)
M39 EMR: Recoil: (144RPM,171RPM) Spread: (237RPM)
M417: Recoil: (180RPM,191RPM) Spread: (250RPM)
SKS: Recoil: (250RPM,263RPM) Spread: (300RPM)
If you think I’m wrong, please correct me. 